read explicit "string" attribute

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Added ability to read the attribute with explicit type "string" of a netcdf variable. 
 - Add ability to connect export of the MAPL hierachy to ExtData via CAP.rc file
 - Added new driver, CapDriver.x, to excerise the MAPL_Cap with the configuratable component also used by ExtDataDriver.x
 - Added Fortran interface to UDUNITS2

pfio/NetCDF4_FileFormatter.F90

@@ -600,7 +600,6 @@ subroutine put_var_attributes(this, var, varid, unusable, rc)
       iter = attributes%begin()
       do while (iter /= attributes%end())
          attr_name => iter%key()
-
          p_attribute => iter%value()
          shp = p_attribute%get_shape()
          if (size(shp) == 0) then ! scalar
@@ -1079,9 +1078,12 @@ subroutine inq_var_attributes(this, var, varid, unusable, rc)
             call var%add_attribute(trim(attr_name), str)
             deallocate(str)
          case (NF90_STRING)
-            !W.Y. Note: pfio does not support variable's string attribute
-            !  It only supports global 1-d string attribute
-            cycle
+            !$omp critical
+            status = pfio_get_att_string(this%ncid, varid, trim(attr_name), str)
+            !$omp end critical
+            _VERIFY(status)
+            call var%add_attribute(trim(attr_name), str)
+            deallocate(str)
          case default
             _RETURN(_FAILURE)
          end select